If you simply want to monitor your email channels, a DMARC policy at p=none is enough. This policy will however not protect you against cyberattacks.
Which DMARC policy prevents spoofing?
A DMARC reject policy is the only DMARC policy that is effective in preventing spoofing attacks. This is because a reject DMARC policy blocks unauthorized emails from reaching your receiver’s inbox, thereby stopping them from accepting, opening, and reading bad emails.